Such connecting means for construction and civil engineering works are known in the prior art in which, when extensible pipe post consisting of an outer tube and an inner tube, two flat boards, and so forth are to be connected, opposed holes are formed in two members as disclosed in for example U.S. Pat. No. 4,348,790, and Japanese Utility Model Publication No. 58-49323, and into these holes are inserted a so-called gravity lock pin for the purpose of connecting both.
The gravity lock pin A as the connecting means is provided with a halved-type cut C in the forward end of a round bar-type body B as shown in FIG. 6, and in this cut C is rotatably installed an engaging piece E through a pivot D, so that the pin A may be inserted into holes of two members to be connected, and after insertion, a lock piece E may rotate out on one side of the shank of the body B, thereby locking with a lock part F.
Since the prior-art pin A has the halved-type cut C formed in the forward end, the forward end part has a low strength, being subject to a crack or a failure.
Furthermore since the lock piece E rotates out only on one side of the shank part of the body B, a force to lock the pin is weak, and accordingly a force in a direction of pulling out is low, resulting in an accidental fall of the pin A in the event that the lock piece E moves toward the inside of the cut C.
Furthermore, in the case of connection between hollow pipes, if this lock piece E moves out, on the way of insertion, with its weight from the shank part of the body in this pipe, the lock piece E will be caught by the inner wall of the pipe, with the result that it will become impossible to remove the pin.